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What happens if you get loss of spark or loss of/poor pattern fuel in one or more cylinders?
Loss of spark in one cylinder => misfire. Poor running car, excessive exhaust manifold temperature, and possibly overheating turbine. As long as enough air flow going thru the cylinder, the fuel will be blown mostly thru the exhaust and I wouldn't expect a hydrolock
Too low octane fuel => knock => ignition retard. Loss of power, excessive exhaust manifold temperature, increased risk of pre-ignition, possibly overheating turbine.
Loss of spark in one cylinder => misfire. Poor running car, excessive exhaust manifold temperature, and possibly overheating turbine. As long as enough air flow going thru the cylinder, the fuel will be blown mostly thru the exhaust and I wouldn't expect a hydrolock
Too low octane fuel => knock => ignition retard. Loss of power, excessive exhaust manifold temperature, increased risk of pre-ignition, possibly overheating turbine.
Right. What I meant was: without some additional gauges what system do you have in place to ‘catch’ this type of degradation in proper AF ratio? AF gauge? Knock indicator light? Or is the waste gate in the control loop for ‘degraded’ mode?
Right. What I meant was: without some additional gauges what system do you have in place to ‘catch’ this type of degradation in proper AF ratio? AF gauge? Knock indicator light? Or is the waste gate in the control loop for ‘degraded’ mode?
Right now, nothing will catch any of those when the car is driven on the street.
AF gauge based on a single post-turbine WB02 sensor wouldn't catch any of the above, if the pre-turbine heat and pressure are such that the mixture burns in the exhaust manifold.
The Q1 2020 project is to install a separate data logging system with sensors to see what is going on with the engine when it's being driven on the street in various conditions. After we are seeing those data in sufficiently large samples, we can start thinking of problem conditions and how to detect them without too many false positives.
AF gauge based on a single post-turbine WB02 sensor wouldn't catch any of the above, if the pre-turbine heat and pressure are such that the mixture burns in the exhaust manifold.
This is still using LH 2.3 right? So, one pot goes lean, the other 7 will go rich. This you will see at the 02 sensor even if it is WB (without ton's of 'plumbing'.)
I'm, based upon my experience with the Twin-Screw, unconvinced that single-cylinder grossly-out-of-spec AF issues will not manifest at a gauge driven by a NBO2 sensor. The opposite actually. It won't tell you which cylinder but it will tell you that something's not right if you know what is supposed to be 'right.'
There's certainly less plumbing between the exhaust and the NBO on mine, but, modern Turbo engines, using NBO2 sensors, pre-cat, will catch minuscule AF issues and then cause "appropriate" engine management strategies to become active (where the value of "appropriate" is dependent upon the imaginations of the folks that wrote the software requirements.)
One item I plan to add to mine is something that indicates knock. Yes, mine is tuned for no knock ever, but that only works in a non-degraded system.
This is still using LH 2.3 right? So, one pot goes lean, the other 7 will go rich. This you will see at the 02 sensor even if it is WB (without ton's of 'plumbing'.)
I'm, based upon my experience with the Twin-Screw, unconvinced that single-cylinder grossly-out-of-spec AF issues will not manifest at a gauge driven by a NBO2 sensor. The opposite actually. It won't tell you which cylinder but it will tell you that something's not right if you know what is supposed to be 'right.'
There's certainly less plumbing between the exhaust and the NBO on mine, but, modern Turbo engines, using NBO2 sensors, pre-cat, will catch minuscule AF issues and then cause "appropriate" engine management strategies to become active (where the value of "appropriate" is dependent upon the imaginations of the folks that wrote the software requirements.)
If all the fuel burns in the exhaust manifolds (high pressure and temperature), then the WBO2 will just get the air and fuel ratio, not the how it was distributed and where it was burned.
There's a provision (as in bungs) in the exhaust manifold to do cylinder specific WBO2 sensors, but cooling and logging eight WBO2 sensors in that engine bay with AEM controllers is a big project.
If all the fuel burns in the exhaust manifolds (high pressure and temperature), then the WBO2 will just get the air and fuel ratio, not the how it was distributed and where it was burned.
If a cylinder is lean, there’s no fuel to burn in the manifold. Over-rich isn’t too worrisome. One or more cylinders lean, is.
Ok, here's some data from the dyno that some of you may or may not be interested in.
The first thing to note is that the engine runs in a cross-over mode up to 735 rwhp @ 5100rpm when run at 25 psi boost limit. That is, the exhaust manifold pressure is lower than the intake manifold pressure up to that point. If the boost limit is increased, it will run at the cross-over mode to even higher power levels. And even with the only 25 psi boost limit, the intake and exhaust manifold pressures are sufficiently close that the valve events etc. work about the same as in a normally aspirated engine. At 810 rwhp air flow, the exhaust-to-intake absolute pressure ratio is still only 1.13x.
The second thing to note is that with all the pipes on and the air filter installed, the static pressure drop to the turbine inlet is only 0.8 psi, which considering the velocities is very good.
The third thing to note is that with 95F ambient air, the intercoolers are dropping the charge temperature from 334F to 122F, or 212F with only 0.3psi pressure drop.
I'd like to see other aftermarket turbo conversion systems with similar pressure and temperature stats.
The boost needs to be turned below 25 psi in the mid range rpms, because it’s making 777 lbf-ft which is a little on the high side for the transmission and clutch. In terms of power, still mapping low rpms so no relevant reading. It makes 806 rw hp at low rpms, so let’s see where it goes as mapping progresses to high rpms.
09-24-2019, 02:26 PM
